III nitride semiconductors formed from compounds in which N is combined with Al, Ga, In, and the like have conventionally been used as materials for ultraviolet light-emitting devices. In particular, III nitride semiconductors made of AlGaN having high Al content are used for ultraviolet light-emitting devices and deep ultraviolet light-emitting devices (DUV-LED) having a light emission wavelength of 300 nm or less.
Examples of the characteristics required of a light-emitting device include high external quantum efficiency properties and low resistance properties. JP 2010-205767 A (PTL 1) describes that a layer serving as an energy barrier for electrons that is called an electron blocking layer is formed between a light emitting layer having a quantum well structure and a p-cladding layer, thereby increasing the light emission efficiency.